Difficult case: Zimmerman claimed he was acting in self-defence when he shot Trayvon Martin on the night of February 26 and has not yet been charged over the incident

A volunteer captain of a Florida neighbourhood watch, who shot dead a black teen and then claimed he acted in self defence, had a 'history of aggressive tactics,' it has today emerged.

Neighbours in George Zimmerman's gated community, at Twin Lakes, near Orlando, had issued complaints about the 26-year-old to local police and the homeowners association before the February 26 shooting, a homeowner said.

Zimmerman has not been charged in the shooting of Trayvon Martin, 17,who was gunned down as he returned to his father’s house with candy for his younger brother.

Martin had been visiting his father from Miami.

According to a police report, Zimmerman, who was patrolling the neighbourhood in his car, had initially called police to report a 'suspicious person in the area'.

Zimmerman was told to keep his distance, but before officers could reach the scene, there was some kind of confrontation between him and Martin.

The teen was shot once in the chest just yards from his father's home. Zimmerman claimed he had fired his 9mm handgun in self-defence and the police say they have no reason to suspect he is lying.

A resident, who attended an emergency homeowner's association meeting after the shooting on March 1, told the Huffington Post how 'one man was escorted out because he openly expressed his frustration because he had previously contacted the Sanford Police Department about Zimmerman approaching him and even coming to his home.

'It was also made known that there had been several complaints about
George Zimmerman and his tactics' in his neighborhood watch role, they added.

Sanford Police Chief Bill Lee, who is leading the investigation into the shooting, and a member of the city council both attended the meeting, according to the homeowner's association newsletter. Neither were available for comment.

Devastated: Trayvon's mother Sybrina Fulton said her 'heart is broken' as Zimmerman has not yet been arrested

Tragic: Martin was coming home with Skittles and iced tea when he was shot dead in the gated community

The complaints against Zimmerman come
amid protests over the killing. The Martin family and their lawyers have
called the shooting an outrage and want Zimmerman arrested. They
believe Zimmerman - who is white - had profiled
the teen, who is black.

Civil rights leaders, including
members of the NAACP and the Rev Al Sharpton, say they are also
preparing to back the Martin family.

Rev Sharpton told the Huffington
Post: 'This case is disturbing to say the least. This is appalling, to
think that this guy admitted to initiating the conversation and that
there was no crime other than the killing of this young man. Yet,
(Zimmerman) is walking around with no threat of an arrest.'

Shot dead: Trayvon Martin was killed as he walked home from a shop at a Florida gated community where his father lives

Police Chief Lee said the investigation into the shooting should be concluded later on today, at a press conference yesterday.

The State Attorney's Office will then decide whether to present it to a grand jury.

The chief was heckled by protestors
during the press conference when he said he did not believe
investigators had enough evidence to charge Zimmerman.

'...there is the right for someone
that has a concealed weapons permit to carry that weapon' he said,
according to local news reports.
'In this case Mr. Zimmerman has made the statement of self defence.
Until we can establish probable cause to dispute that, we don’t have the
grounds to arrest him.'

A police report said Zimmerman
reported a suspicious person in the neighbourhood and minutes later 911
dispatchers received several calls of shots being fired in the
neighborhood.

Zimmerman told police officers that he had shot Martin and officers found a semiautomatic handgun on him.

The report said that Zimmerman's back
was wet and he was covered in grass as if he had been on the ground. He
was bleeding from his nose and the back of the head, the report said.

A police officer said he overheard
Zimmerman say, 'I was yelling for someone to help me but no one would
help me' while he was being treated by paramedics.

On
Thursday, the family said they were suing police to get access to 911
calls in the case, which they believe could provide clues to Trayvon’s
death.

Police say the 911 recording is evidence in the on-going investigation.

Martin's father, Tracy, said that family members were upset that no arrest had been made.

Exclusive: The entrance to the gated community where Martin was shot

The family's attorneys also questioned why a neighbourhood watch leader would carry a gun.

'He was stereotyped for some reason,' the Martins' attorney Ben Crump said of the victim.

'Why was Trayvon suspicious? There are hundreds of children in that community.’

Mr
Crump also called Zimmerman a ‘loose cannon’ and pointed out that
Zimmerman was arrested in Orange County in 2005 for resisting arrest and
battery of a police officer.